


Assassin

by bisexuallaurel



Category: Shadowhunters (TV)
Genre: AU, Alternate Universe - College/University, Assassin (the game), M/M, Mild Smut, Prompt Fill
Language: English
Status: Completed
Published: 2017-01-21
Updated: 2017-01-21
Packaged: 2018-09-19 02:14:19
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,964
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/9413264
Author URL: https://archiveofourown.org/users/bisexuallaurel/pseuds/bisexuallaurel
Summary: Jimon College AU.A game of Assassin leads to a scandalous betrayal. Can Jace and Simon get through it together? Spoiler alert: yes, they can. But will their blue balls survive with them? Spoiler alert: yes, they will.Fill for the sentence prompt "I know you know". Cross-posted on Tumblr (link & content warnings inside).





	

**Author's Note:**

  * For [bluenna](https://archiveofourown.org/users/bluenna/gifts).



> Content warnings:  
> \- biting kink (brief mentions)
> 
> Read it on tumblr:  
> http://bi-magnus.tumblr.com/post/156186762149/i-know-you-know-jimon

When Jace throws the door open and storms into the room, Simon immediately shouts, “I swear I don’t know!”

Jace slams the door shut behind him and quickly advances on Simon, who puts up his hands in surrender. Simon is breathless after the chase and has to take a few moments to even out his breathing.

“Dude I promise, I don’t know,” he repeats when he’s caught his breath enough to speak, but it doesn’t matter. Jace is still moving towards him. For every two steps he takes, Simon moves back one until he is backed up against the wall.

Jace narrows his eyes. He’s still a few steps away from Simon when he stops. “Where are they?”

Simon shakes his head. “I don’t know.”

“Damnit, Lewis! I know you know!” Jace snaps.

“I don’t! I haven’t seen them since––”

“You’re lying and we both know it,” Jace says. It’s like his eyes are boring into Simon’s soul and searching every inch of it.

“My dude, I’d tell you if I could, but I. Don’t. Know.”

At that, Jace closes the distance between them and physically presses Simon against the wall. With a hand flat on Simon’s chest pushing him back, he growls, “Tell me.”

Their faces are mere inches apart. Simon’s heart beats steadily beneath Jace’s fingertips and for a few moments, there is nothing but silence around them.

Simon bites his lip.

Jace glowers at him. Then he glances down at where his fingers are splayed over Simon’s Star Wars shirt. There is nothing but fabric beneath his fingers; no sharp edges, no plastic smoothness. Suddenly all the pieces fit together.

“Motherfucker,” Jace hisses, and jerks his hand back. “Who got you?”

“Magnus,” Simon confesses. His posture relaxes and he grins broadly, like he’s been dying to do it for hours. “He got me yesterday.”

“You tricked me,” Jace says accusatorially.

“I did,” Simon says proudly.

“And what, they’re in on it too?”

“Mhm,” Simon says, “They’re waiting outside the dorms for you.”

Jace’s jaw drops. “Even Alec?”

“Especially Alec,” Simon confirms. “He and Izzy spearheaded the mission.”

“I can’t believe them,” Jace says, pacing back and forth. He turns back to Simon. “I can’t believe you!”

“You’re making it sound like I sold you out to some terrorists,” Simon laughs, but he immediately stops when he sees Jace’s tense jaw. He smiles playfully. “Oh come on, are you really angry?”

“I’m hurt that you would side with my siblings over me,” Jace says grumpily. He crosses his arms over his chest and looks away. Then he adds, as if he just can’t resist asking, “Are you even allowed to play if you’re eliminated?”

Simon nods. “Yep. I checked with Luke and since he co-wrote the school rules…”

“Whatever,” Jace huffs.

“He said I can interfere but I can’t, you know, kill anyone,” Simon says for clarification. Jace just mutters something unintelligible in response.

“Jace…” Simon says softly. He walks up to Jace and puts his hand on his bicep. He opens his mouth to speak and then interrupts himself by pretending to be surprised by how fit Jace is. “Wow, have you been working out?”

Even Jace can’t help but smile at that.

He shakes his head and then uncrosses his arms.

“Aw, see, you do have a heart,” Simon says, and tries to wind Jace’s arms around himself. At first Jace doesn’t participate at all; he just limply hangs his arms and makes Simon do all the work while secretly smiling to himself.

Simon perseveres and, granted, it’s not the best hug in the world at first, but once he’s struggled with it for a while, Jace gives in and hugs him back.

“I still don’t forgive you though,” Jace says into Simon’s hair.

“It’s just Assassin, Jace. You’ll forgive me,” Simon says, and it takes Jace a few moments to decipher his words since Simon’s face is currently nuzzled against Jace’s neck.

“I could always just use you as a human shield,” Jace muses.

Simon kisses his neck. “No, you can’t.”

“No, I can’t. I mean I can, but I won’t.”

“I’ll wrestle you to the ground before I let you do that.”

Jace leans back and looks at Simon. “You would wrestle me? Really?”

Simon leans back too, and nods. “I would.”

They both consider each other for a second and then at the exact same moment, they grab hold of each other and start twisting and turning to get the other onto the floor.

As a way of atoning for his betrayal, Simon lets Jace win.

“Oh nooo, you beat me. Darnit.”

Jace is straddling his waist and pinning down his wrists against the floor.

“You’re not really in a position to make fun of me, you know,” he says.

“What’re you gonna do? Tickle me?” Simon asks, confident in the fact that he’s not the least bit ticklish.

Jace seems to consider this for a moment, and then he smiles. A slow, sweet smile, with a dangerous edge to it.

Before Simon can react, he’s grabbed both of Simon’s wrists in one hand and pinned them to the floor, leaving the other hand free.

“Incredible,” Simon says. He means it sarcastically, but he also finds himself quite… affected by the fact that Jace only needs one hand to trap him this effectively.

“No, but you are,” Jace says silkily, and places a gentle kiss right beneath Simon’s jawline.

Simon tenses. Well, this was unexpected.

More kisses are pressed to Simon’s jaw, cheek, earlobe, and neck; each one softer than the other. Jace keeps kissing every inch of him from the neck up –– everywhere except for on the mouth.

“What are you doing?” Simon laughs, and strains against Jace’s grip to reach up and kiss him.

Jace hums under his breath and keeps doing his little kiss trail without answering the question.

And then, without any warning whatsoever, he rolls his hips against Simon’s.

Simon, who is completely taken by surprise, moans.

He wants to slap a hand over his mouth but he obviously can’t. Instead all he can do is angle his head so he can look Jace in the eye, and say, “Seriously, what are you doing?”

“This,” he says softly, and places another kiss to the corner of Simon’s mouth, “is revenge for betraying me.”

“Your revenge is turning me on?” Simon asks incredulously. “Honey, that’s not a punishment.”

“No,” Jace says patiently. He rolls his hips again and Simon makes a little whining noise in the back of his throat.

“Then what are you–– ohhhh.”

Jace cuts him off by attaching his lips to his jugular vein and sucking. Hard.

As he does so, he very slowly skims his hand down Simon’s body and slides it under the small of his back. With his palm flat against Simon’s skin, he pushes him up so their bodies are flush against each other.

Simon’s breath catches and he starts to say something but trails off as he gets lost in the sensation of Jace’s touch.

When Jace finally moves on from Simon’s neck, he’s left several hickeys in his wake. Simon’s breathing is considerably more shallow now and with every kiss he feels his sanity slipping further from his grasp.

He can’t for the life of him remember what they had been talking about before Jace started kissing him, and parts of him doesn’t even want to. Everything that matters is that right now, all he needs is Jace; closer, and closer still.

Jace shifts and slides back onto Simon’s thighs. His grip still firm on Simon’s wrists, he brings his boyfriend’s arms down with him so Simon’s hands rest on his chest. With a look, he makes sure that Simon’s still aware of the terms: he can’t move.

Once Simon has nodded his confirmation, Jace carefully rolls up the hem of Simon’s t-shirt, leaving his stomach exposed. With his palm flat against Simon’s abs, he drags his hand down the expanse of skin; his nails catching at the course hairs trailing down from his belly button.

Then Simon chokes out a strangled word that sounds suspiciously like Jace’s name as his hand slides down to the brim of his boyfriend’s jeans. A finger dips down beneath the waistband of his boxers, and then immediately retreats.

“Jace, I swear to––”

Jace silences him with a look, and Simon exhales shakily.

He slowly, unfairly slowly, unzips Simon’s jeans. He doesn’t attempt to take them off and instead seems satisfied focusing on the zipper.

“You’re not usually this slow to get me naked,” Simon says in an attempt to gain back some of the control he’s given away, but Jace isn’t having it. He smirks and removes his hand completely.

“Okay, okay, I’ll shut up, I’ll be good, I swear,” Simon says quickly. He would be embarrassed by how completely desperate he sounds, but he and Jace have long been past the point in their relationship where they’re embarrassed to show desperation in bed.

Jace seems satisfied with this development, because his hand slowly drags down Simon’s side again, and settles right over his bulge.

Simon wants to tell him to "please just fucking do something", but he doesn’t. Instead he turns his head and kisses the inside of Jace’s arm, which happens to be just about the only part of Jace he can reach.

Jace rewards by stroking him over his boxers; firm, long strokes that leave Simon whimpering under his touch. Simon tries not to buck up into Jace’s hand but it’s close to impossible. It feels so good but he still needs more.

As if Jace can read his mind, he picks up the pace. His hand moves faster and the pressure in Simon’s belly keeps building and building. It’s so good and every drag of Jace’s hand is incredible.

Simon closes his eyes and lets his head fall back against the floor. He can feel himself getting closer with every stroke and he wants to kiss Jace so badly, but he’ll take “no kiss sex” over “no sex” any day.

“Fuck, Jace,” he groans, and digs his nails into his palms. His body lifts off the floor in a tense arch. “Babe I’m close, I’m so––”

Jace abruptly pulls his hand away.

Simon makes a choking noise as he drops back to the floor in disappointment. He cranes his head to look at his boyfriend; his eyes are glazed over with lust and he has to struggle to keep them focused. 

Without saying anything, Jace moves back to straddle Simon’s hips, very carefully making sure not to touch Simon’s throbbing dick. He tops it off with a single, closed-mouthed kiss on Simon’s jaw.

Then, just when Simon opens his mouth to protest, Jace delivers the final blow and sinks his teeth into Simon’s neck.

Simon hisses, and involuntarily bucks his hips.

“Oh that’s not fair,” he groans, and tries against his better judgment to press himself closer to Jace. The fabric of his jeans is rubbing uncomfortably against his dick and every time Jace grinds down against him, it’s simultaneously the best and the worst thing.

“The punishment,” Jace whispers, as he soothes the bite mark with his tongue, while simultaneously grinding down against Simon, “is that I won’t get you off.”

And with that, he lets go of Simon’s wrists, and gracefully climbs off Simon’s body.

Simon just stays on his back, staring incredulously at his boyfriend.

“You can’t be that cruel,” he says.

Jace shrugs. “Apparently I can.” He smiles far too sweetly.

Simon sits up and just stares at him. His zipper is still down, his neck is covered in hickeys and he’s quite frankly looking a mess. And after all that, he didn’t even get to come.

“I don’t–– I––”

His brain has melted out of his ears and he can’t put together the pieces to understand why this happened.

Jace smiles innocently and extends a hand to help Simon to his feet. He takes it, but still looks very much confused.

Jace kisses the tip of his nose.

“Ready to see me eliminated?” he asks.

To him, all animosity is gone now that they’re square, although Simon doesn’t seem to think so.

“You––” Simon clears his throat. “If you love me…” he continues, with his very best wounded animal voice.

“Oh no, honey,” Jace says happily. “You betrayed me, I betrayed you. We’re even.”

“We haven’t had sex in two weeks,” Simon whines. He quickly abandons his first strategy when it clearly didn’t work. “Just because you’ve been too paranoid about Assassin to fuck your boyfriend. I just want my boyfriend back, isn’t that an honorable reason to betray you?”

“Nope,” Jace says, still smiling. He’s by no means unaffected by their little grinding session, but his self-control is famously better than Simon’s. Most of the time. Well, sometimes. And as much as he, too, wants to have sex right now, he also desperately want to win the campus-wide game of Assassin.

Simon groans. “Okay, you’re right. Clary convinced me to help them. But she’s my best friend, what was I supposed to do?”

Jace shrugs. “I don’t blame you, but you made your decision and so have I.”

“Oh well, let’s get you killed then,” Simon sighs. But just as Jace is about to turn to leave, he dramatically adds, “As long as you can live with yourself knowing you broke my heart… and my boner.”

Jace just laughs. “Who’s dramatic now?”

“Alright,” Simon says, finally admitting defeat. Then he says, in a softer voice, “They’re probably in the hallway by now, but if you climb out the window, you can get away.”

After everything he’s tried, that actually gets through to Jace.

His eyes soften and his shoulders lose some of their tension.

“Really?”

“Yeah,” Simon says. “But seriously, don’t fucking make me wait another week. Just… get them soon, okay?”

But Jace doesn’t escape out the window. He doesn’t go out into the hallway to face his destiny either.

Instead he rips off the polaroid photo hanging around his neck, throws it on the floor, and sweeps Simon off his feet –– literally.

Simon lets out a giggle and then a squeal as Jace all but throws him on Simon’s bed and climbs on top of him.

“You’re really giving up the game for me?” Simon asks, and even though he was so confident before, he’s starting to feel bad about it now. Jace has put in a lot of time and effort into the game for a reason, and suddenly it doesn’t feel right to make him give that up.

“You made your decision and so did I,” Jace echoes his own words from earlier. Then he adds, “Seriously, it’s fine. I just wanted to beat Alec and Iz but I can do that next year.“

“You sure?”

Jace nods solemnly. Then he smiles, and this time it’s not for manipulation or seduction. It’s his private smile, the one almost only Simon gets to see.

“I love you,” Simon says, and pulls him down for a kiss, finally.

He can feel Jace smiling into the kiss and it makes his heart flutter. Being with Jace is a rollercoaster of emotions and he never thought he could be this happy.

Just as he’s about to be really, really happy, the door slams open.

Simon yelps in surprise and almost knocks Jace off the bed when he hurls himself after the covers.

In the door stands Clary, Izzy and Alec. Alec’s mouth is open to speak, but no words come out.

“On the floor,” Jace says without prompting, and then casually leans back on his elbows. Simon has the covers up to his chin, even though he’s still very much wearing all his clothes.

Clary picks up the discarded polaroid and slips it into her pocket. “What about your kills?”

She seems wholly unperturbed by the scene she’s walked in on.

“Maybe we should come back later,” Alec says. He’s looking anywhere but at his brother’s very visible boner.

“No, we need all the polaroids,” Clary insists.

She is, just as Jace, very invested in winning. Normally he would feel some level of bitterness at losing to her again, but all he feels is a pleasant buzzing in the pit of his stomach as he looks over at Simon. Simon looks deeply uncomfortable, so Jace takes his hand and squeezes it.

“The kills are on the desk,” Jace tells Clary, and then mutters to Simon, “D’you think they’ll leave if we just start having sex?”

“If I’m this uncomfortable having sex in front of my best friend who’s like a sister, you should be more uncomfortable having sex in front of your actual sister,” Simon whispers back.

“That’s how hot you are,” Jace replies, grinning. “I’m willing to––”

“We can still hear you,” Izzy says abruptly.

Alec has promptly left the room, but Izzy is still standing in the door while Clary look for the polaroids. She’s wearing her trademark Lightwood smirk.

“You know what,” Jace says then, smirking back at her. “Look for the photos, don’t look for them, I don’t care. I’ll be blowing my boyfriend whether you’re here or not, so the decision’s up to you.”

Then he turns to Simon and kisses him; his hands sliding into Simon’s hair after guiding Simon’s hands to the small of his back. Simon snickers into the kiss. His nerves are quickly dissolving as he melts into Jace.

That seems to do the trick, because both Izzy and Clary hastily leave the room, polaroids in hand.

“Be safe, boys!” Izzy calls as she closes the door behind her, and Jace can hear the smirk on her face.

“Speaking of safety…” Jace whispers against Simon’s lips.

Simon grins.


End file.
